Acoustic device



May 19, 193.6. D, F, BURKE 2,041,163

ACOUSTIC DEVICE Filed Maron 9, 1954 Patented May 19, 1936 yUNITED STATES PATENT OFFICE 17 Claims.

This Vinvention relates to improvements in magnetic plate diaphragms of telephone receivers and other sound devices where a vibratable disc is used and is an improvement over the inventions disclosed in my applications Serial No. 546,771 and No. 640,635, led June 25, 1931 and November l, 1932 respectively. More speciiically the invention relates to a mounting and controlling means for the diaphragm.

In telephone receivers in which a. disc` is caused to vibrate by electro-magnetic means and electric energy is translated into acoustic energy, it has heretofore been customary to clamp the disc iirm'ly along all oi the periphery of the diaphragm between two flanges in order to insure the highest efliciency in the response of such diaphragms to electric stimulation.

The object of this invention is to provide a diaphragm for instruments of the character mentioned, so constructed and arranged that there will be a marked increase both in the intensity and in the quality of the tones emanating therefrom as compared with the usual diaphragm that has been in use many years and furthermore that this increase of intensity and quality operates whether the electric stimulation is of low or high intensity.

A further object of this invention is` to provide a low cost means for and a method of damping telephone receiver diaphragms.

A further object of this invention is tomould magnetic plate diaphragms on the same diameter at each side of the center portion of the diaphragm into the desired S-shaped form along the extremities of one diameter and the provision of means for preserving this form when under such resistive forces as clamped diaphragms are operated.

A further object of this invention is to provide a means for and a method of mounting magnetic plate diaphragms in acoustic devices of this kind in such a manner that the desired mounting will be preserved when the receiver ear-piece is adjusted to the interior body-piece member by screw pressure, and when the instrument is subjected to rough handling and to changes of humidity, temperature and location.

A further object of this invention is to provide a means for and a method of mounting and controlling diaphragms of this kind in such a manner as to permit a greater iidelity of reproduction of sound Waves over a wider band of frequencies than has heretofore been attained with this type of diaphragm.

A further object of this invention is to mould this type of diaphragm in such a manner that the improved diaphragm will be more sensitive in response to signals of low electrical intensity than diaphragms heretofore used in the art, when mounted in proper operating position with the same amount of air gap between the magnet and diaphragms.

A further object of this invention is to provide a means for and a method of dam-ping diaphragms of this type in such a manner that the natural diaphragm resonance point is removed from the useful range of voice frequencies as compared with the resonance point of diaphragmsused heretofore.

The invention contemplates moulding this type of diaphragm in such a manner as to introduce four dishings along one diameter of the .diaphragm, one inward dishing from the plane of the seat on either' side of the center portion, adjacent to the periphery and one dishing outwardly from the plane of the seat and the magnetic impulsing combination at each extremity of the diameter. It also contemplates provision for the preservation of such dishings under operating conditions, by the introduction of two hard metal strips arranged in the peripheral dishings between the diaphragm and the seat of the receiver, the dished peripheral portions remaining secured against peripheral stretching, or gripping, or elongation, or relative flattening, the opposite parts of the dished peripheral portions of the diaphragm clamped, for security against rigid clamping of the majority portion of the diaphragm such that the diaphragm is substantially free to move at its majority peripheral portion.

The invention resides, essentially, in clamping the moulded magnetic plate diaphragm intermediarily and firmly only at two points at the extremties of a diameter and arranging a pair of strips between the seat and the diaphragm, and allowing most of the peripheral portion of the diaphragm a certain amount of freedom from firm clamping to the seat for most of the peripheral portion and supported on the seat by the pull of the magnet. Furthermore, this invention contemplates moulding this type of diaphragm and also mounting same in the above described manner in order to increase the elasticity of same and the damping factor of same, causing an increase of physical intensity and a clearer wave form of the tones emanating therefrom as compared with the older diaphragms.

In other words the overlapping of the same components vof the complex tone for the improved diaphragm is less than the overlapping of the same Various components of the complex tone for the old diaphragm. Consequently the time damping is greater for the improved diaphragm than for the old form of diaphragm.

The invention consists in a moulded diaphragm as set forth in the following specications and particularly as pointed out in the claims thereof.

Referring to the drawing:

Fig. 1 represents an enlarged side elevation of a telephone receiving instrument, an end portion thereof being broken away and illustrated in section, thereby exposing the essence of this invention with enlarged diaphragm and S-shaped dishings thereof, and exposing the mode of arranging the strips of this invention.

Fig. 2 is an exploded plan view of the diaphragm, showing the inner surface of the diaphragm that is operatively nearer the magnet.

Fig. 3 is a detail drawing of the exploded view of the diaphragm showing the contour of the diaphragm in the area where the diaphragm is clamped against the strips of this invention.

Fig. 4 is a detail drawing of the exploded View of the diaphragm showing the contour of the diaphragm where it is dished inwardly toward the plane of the receiver seat and magnetic impulsing combination.

Fig. 5 is a plan view of the diaphragm designated by I5d illustrating the inward dishings of the diaphragm towards the plane of the seat of the receiver and magnetic impulsing combination and adjacent to the peripheral portions thereof and the outer dishings at the peripheral portions in the clamping areas.

Fig. 6 is a plan view of the strips and illustrating the position of the strips when made integral with the receiver seat, designated by I6.

Fig. 7 is a plan View of the diaphragm designated by I5e` showing the contour of the surface of the diaphragm from which sound energy emanates in the inner face.

Fig. 8 is a plan view of the seat of the receiver illustrating the position of the recesses made in the seat designated by I9, of the telephone receiver.

Fig. 9 is an enlarged detail section illustrating how the strips may be made integral with the diaphragm.

Fig. 10 is a detail section showing the S-shaped dishings on one diameter at each side of the center portion of the diaphragm of this invention.

Like numerals refer to like parts throughout the several views of the drawing.

In the drawing, I0a represents a broken-off telephone receiving instrument embodying therein a hand-piece IIa, ear-piece known in the art as a cap I2a, interior body-piece member I3, and electro-magnet I4, and a seat I9, all of which are assembled in a well known manner and are old and Well known in the art.

Clamped between the adjacent faces of the interior body-member I3 and the ear-piece I2a, is a diaphragm I5 which differs from the old form of diaphragm in that it presents, on either side of the center portion, along one diameter, and adjacent to the clamping area and in reference to the plane of the seat I9 a small inward dishing 2|, and adjacent to the above dishing and within the clamping area and from the plane of the seat I9, an outward dishing 22, and the preferred embodiment of this invention contemplates maintaining tlie latter dishings, which would otherwise be flattened out by the screw-pressure of the ear-piece in operating position, by arranging L- shaped strips of hard metal I6, approximately .01 inch in thickness and .06 inch in width between the diaphragm I5, and the seat I9, in the space made possible by the peripheral dishing, as described above. It is obvious that such an arrangement of the diaphragm supported on the strips will cause the diaphragm to be somewhat free from rigid clamping along most of its periphery and will be supported on the seat by the pull of the receiver magnet I4.

The strips I6, are retained in proper operating position by disposing them in recesses I'I, made in the seat I9, and in the body-member I3, as illustrated in Fig. l. This is the preferred form but the strips I5, may be made integral with the seat I9, as illustrated in Fig. 5, or the strips may be made integral with the diaphragm I5, as illustrated in Fig. 9.

Fig. 9 shows cross-section of diaphragm with strips made integral I6.

Fig. 9 illustrates a detail section of the diaphragm with portions oi greater thickness than the rest of the diaphragm.

The ear-piece I2 screws on to the interior bodypiece I3 in operative relation. Member I3 is threaded to receive I2.

While I have described the metallic strips as being constructed of metal and as being approximately .25 inch long by .0l inch in thickness by .06 inch in width, it is evident that these dimensions may be varied, or the form of said members may be varied, or they may be constructed of other materials having the same properties as metal, or a multiple of strips arranged to permit yielding under stress as long as sufficient resistive force is offered to maintain the desired peripheral dishing of the diaphragm, without departing from the spirit of the invention.

In the attached claims the use of the expression outer abutment means the ear-piece I2a or an equivalent contrivance sustained by the interior body-member I3 and used in this invention as a rigid or substantially rigid shoulder to which can be adjusted to bear against predetermined dished portions, designated by 22, of the diaphragm I5. By the term casing used in the attached claims, is meant the interior body-member I3. The expression magnetic impulsing combination means the electro-magnet and coils.

While I have described in the foregoing specification, a preferred embodiment of my invention, I do not wish to be limited to the construction of diaphragm shown and described, but claim broadly the invention set forth in each and all of the following claims.

I claim:

1. A magnetic plate diaphragm for a telephone receiver, embracing a casing supplied with a seat, a magnetic diaphragm impulsing combination within said casing, said combination having been iixed with reference to the seat, said diaphragm having a pair of dishings arranged outwardly from the plane of said seat and said combination, and said dishings disposed in the periphery of said diaphragm and located diametrically opposite each other and said diaphragm being substantially free to move over its major peripheral portion.

2. A magnetic plate diaphragm for a telephone receiver, embracing a casing supplied with a seat, a magnetic diaphragm impulsing combination within said casing, said combination having been xed with reference to said seat, said diaphragm having a pair of dishings arranged outwardly from the plane of said seat and said combination, and said dishings disposed in the periphery of said diaphragm. and located diametrically opposite each other, and a pair of dishings arranged inwardly from the plane of said seat and disposed diametrically opposite each other and located between the center portion and peripheral portions of said diaphragm and adjacent to the: peripheral dishings thereof and said diaphragm being substantially free to move over its major peripheral portion.

3. A magnetic plate diaphragm for a telephone receiver, embracing a casing supplied with a seat, a magnetic diaphragm impulsing combination within said casing, said combination having been Xed with reference to said seat, said diaphragm having a pair of dishings arranged inwardly from the plane of said seat and located diametrically opposite each other and disposed between the center portion and the peripheral portions of said diaphragm and said diaphragm being substantially free to move over its major peripheral portion.

4. A magnetic plate diaphragm for a telephone receiver, embracing a casing supplied with a seat, a magnetic diaphragm impulsing combination within said casing, said combination having been xed with reference to said seat, said diaphragm having a pair of dishings arranged outwardly from the plane of said seat and said combination, and said dishings disposed in the periphery of said diaphragm, and located diametrically opposite each other and a pair of dishings arranged inwardly from the plane of said seat and disposed diametrically opposite each other and 1ocated between the center portion and the peripheral portions of said diaphragm and metallic strips adhering to and contacting with the inner face of said diaphragm in said dished peripheral portions and said diaphragm being substantially free to move over its major peripheral portion.

5. A telephone receiver embracing a casing supplied with a seat and a pair of metallic strips supported on said seat and arranged to rest astride said seat, and disposed on the extremities of one diameter of said seat, and arranged diametrically opposite each other, a magnetic diaphragm impulsing combination within said casing, a magnetic plate diaphragm and along one diameter of said diaphragm a pair of dishings outward from the plane of said seat and said combination, and arranged oppositely on the same diameter in peripheral portions thereof, and along the same diameter a pair of dishings inward from the plane of said seat, and arranged oppositely on the same diameter and disposed between the center portion and said peripheral portions and said dished diaphragm placed over said diaphragm impulsing combination, and said strips arranged on said seat between said seat and said dished peripheral portions of said diaphragm, and said dished peripheral portions arranged to bear against said strips, and an outer abutment and rigid means disposed between the outer side oi the marginal portion of the diaphragm and said outer abutment and adapted to apply a resisting pressure against said dished peripheral portions of said diaphragm, the dished peripheral portions remaining secured against peripheral stretching, or gripping, or elongation, or relative ilattening, the opposite parts of said dished peripheral portions of said diaphragm being clamped, and said diaphragm being substantially free to move over its major peripheral portion.

6. Atelephone receiver embracing a casing supplied with a seat, multiple recesses arranged oppositely on the extremities or" the same diameter of said seat in the boundary line of peripheral portions of said seat, multiple recesses arranged oppositely on the same diameter in the screwthreaded rim of the interior body-part and disposed directly below said recesses in said seat, a pair of metallic strips supported on said seat and one leg of each strip disposed in each of said recesses, a magnetic diaphragm impulsing com bination within said casing, a magnetic plate diaphragm placed over said diaphragm impulsing combination, and along one diameter of said diaphragm a plurality of dishings outward from the plane of said seat and arranged oppositely on the same diameter in peripheral portions thereof, and along the same diameter a pair of dishings inward from the plane of said seat and arranged oppositely on the same diameter and disposed between the center portion and said peripheral dishings, and one leg of each strip arranged between the dished peripheral portions of said diaphragm and said seat, and said dished peripheral portions arranged to bear against one of said legs of each of said strips, and an outer abutment and rigid means disposed between the outer side of the marginal portion of the diaphragm and said outer abutment and adapted to apply a resisting pressure against said dished peripheral portions of said diaphragm, the dished peripheral portions remaining secured against peripheral stretching, or gripping, or elongation, or relative ilattening, the opposite parts of said dished peripheral portions of said diaphragm being clamped and said diaphragm being substantially free to move over its major peripheral portion.

7. A telephone receiver embracing a casing supplied with a rigid seat, a magnetic diaphragm impulsing combination within said casing, said. seat having very small portions thereof of greater longitudinal thickness than the seat proper, and said thickened portions of Said seat being located diametrically opposite each other and disposed on the extremities of one diameter, and projecting from seat proper, and a magnetic plate diaphragm, and along one diameter of said diaphragm a pair of dishings outward from the plane of said seat and said magnetic diaphragm impulsing combination and arranged oppositely on the same diameter in peripheral portions thereof and along the same diameter a pair of dishings inward from the plane of said seat and arranged oppositely on the same diameter and disposed between the center portion and said peripheral portions, and said dished diaphragm placed over said diaphragm impulsing combination, and supported by said thickened portions of said seat, and against which said dished peripheral portions of said diaphragm rest, and an outer abutment and rigid means disposed between the outer side of the marginal portionA of the diaphragm and said outer abutment and adapted to apply a resisting pressure against said dished peripheral portions of said diaphragm, the dished peripheral portions remaining secured against peripheral stretching, or gripping, or elongation, or relative flattening, the opposite parts of said dished peripheral portions of said diaphragm being clamped and said diaphragm being substantially free to move over its major peripheral portion.

8. A telephone receiver embracing a casing supplied with a seat, a magnetic diaphragm impulsing combination within said casing, a magnetic plate diaphragm placed over said magnetic diaphragm impulsing combination, said diaphragm comprising a thin disc having metallic strips made integral with said diaphragm and said strips located diametrically opposite each other on said peripheral portions of said diaphragm and disposed in reference to the plane of said seat on the inner face of said diaphragm, and along the same diameter of same diaphragm a pair of dishings inward from the plane of said seat, and said dishings arranged oppositely on the same diameter and disposed between the center portion and said peripheral portions, and a pair of outward dishings from the plane of said seat, and said outward dishings arranged oppositely on the same diameter and adjacent to and partly surrounding'said strips of said diaphragm, and said thickened portions supported by said seat, against which said strips rest, and an outer abutment and rigid means disposed between the outer side of the marginal portion of the diaphragm and said abutment and adapted to apply a resisting pressure against the dished peripheral portions of said diaphragm, the dished peripheral portions remaining secured against peripheral stretching, or gripping, or elongation, or relative flattening, the opposite parts of said dished peripheral portions of said diaphragm being clamped and said diaphragm being substantially free to move over its major peripheral portion.

9. In a telephone receiver, a magnetic plate diaphragm and means for enclosing said diaphragm, said means comprising a cap and a seat, and means for exerting a resisting pressure of said cap in the direction of said seat, said diaphragm comprising a thin, flexible, resilient disc, having a pair of strips disposed in reference to the obverse face thereof, on the inverse face of said diaphragm, and said strips being located diametrically opposite each other along one diameter of said diaphragm and disposed in peripheral portions of said inverse f ce of said diaphragm, the dished peripheral portions remaining secured against peripheral stretching, or gripping, or relative flattening, or elongation, the opposite parts of said dished peripheral portions of said diaphragm being clamped for security against rigid clamping over the major peripheral portion of said diaphragm between said cap and said seat, said diaphragm being substantially free to move over its major peripheral portion.

10. In a telephone receiver, a magnetic plate diaphragm, and means for enclosing said diaphragm, said means comprising a cap, and a seat, and means for exerting a resisting pressure of said cap in the direction of said seat, said diaphragm comprising a thin, flexible, resilient disc, having a pair of strips disposed, in reference to the obverse face thereof, on the inverse face of said diaphragm, and said strips being located diametrically opposite each other along one diameter of said diaphragm and disposed in peripheral portions of said inverse face of said diaphragm and said strips arranged to extend centripetally a predetermined distance on said diameter, the dished peripheral portions remaining secured against peripheral stretching, or gripping, or elongation, or relative flattening, the opposite parts of said dished peripheral portions of said diaphragm being clamped for security against rigid clamping over the major peripheral portions of said diaphragm between saidcap and said seat, said diaphragm being substantially free to move over its major peripheral portion.

11. In a telephone receiver, a magnetic plate diaphragm, and means for enclosing said diaphragm, said means comprising a cap, and a seat, and means for exerting a resisting pressure of said cap in the direction of said seat, said diaphragm comprising a thin, flexible, resilient disc, and in reference to the obverse face thereof, a pair of strips fastened to the inverse face of said diaphragm and disposed in peripheral portions thereof, the dished peripheral portions remaining secured against peripheral stretching, or gripping, or elongation, or relative flattening, the opposite parts of said dished peripheral portions of said diaphragm being clamped for security against rigid clamping over the major peripheral portion of said diaphragm between said cap and said seat, said diaphragm being substantially free to move over its major peripheral portion.

12, In a telephone receiver, a magnetic plate diaphragm, and means for enclosing said daphragm, said means comprising a cap and a seat, and means for exerting a resisting pressure of said cap in the direction of saidseat, said diaphragm comprising a thin, flexible, resilient disc, and in reference to the obverse face thereof, a pair of strips fastened to and in contact with the inverse face of said diaphragm and disposed in peripheral portions thereof, the dished peripheral portions remaining secured against peripheral stretching, or gripping, or elongation, or relative flattening, the opposite parts of said dished peripheral portions of said diaphragm being clamped for security against rigid clamping over the maior peripheral portion of said diaphragm between said cap and said seat, said diaphragm being substantially free to move over its major peripheral portion.

i3. In a telephone receiver, a magnetic plate diaphragm, and means for enclosing said diaphragm, said means comprising a cap, and a seat, and means for exerting a resisting pressure of said cap in the direction of said seat, said diaphragm comprising a thin, flexible, resilient disc, and in reference to the obverse face thereof, a pair of strips fastened to and in contact with the inverse face of said diaphragm and said strips arranged to extend centripetally a predetermined distance along one diameter thereof, the dished peripheral portions remaining secured against peripheral stretching, or gripping, or elongation, or relative flattening, the opposite parts of said dished peripheral portions of said diaphragm being clamped for security against rigid clamping over the major peripheral portion of said diaphragm between said cap and said seat, said diaphragm being substantially free to move over its major peripheral portion.

14. A telephone receiver embracing a casing supplied with a seat, a pair of recesses arranged in the boundary line cf peripheral portions of said seat, multiple recesses arranged in the screwthreaded rim of the interior body part of said casing, and -disposed directly below said recesses in said seat, a magnetic plate diaphragm and along one diameter of said diaphragm, and in reference to the obverse face thereof, a pair of strips fastened to and projecting from the inverse face and said strips located in peripheral portions of said diaphragm, and one leg of each strip arranged to rest in said recesses, and along the same diameter a pair of dishings inward from the plane of said seat, and arranged oppositely on the same diameter and disposed between the center portion and said peripheral portions of said diaphragm, a magnetic diaphragm impulsing combination within said casing, and said dished diaphragm placed over said magnetic diaphragm impulsing combination, and one leg of each of said strips disposed diametrically opposite each other on said seat, and an outer abutment and rigid means disposed between the outer side of the marginal portions of said diaphragm and said outer abutment and adapted to apply a resisting pressure against said peripheral portions of said diaphragm, the dished peripheral portion remaining secured against peripheral stretching, or gripping, or elongation, or relative flattening, the opposite parts of said dished peripheral portions of said diaphragm being clamped for security against rigid clamping of the major peripheral portion of said diaphragm between said cap and said seat, said diaphragm being free to move over its major peripheral portion.

15. A telephone receiver as set forth in claim wherein, hereinbefore, the magnetic plate disc in devices of this class, is rigidly clamped against the whole of the receiver seat, is, in this device, free from such rigid clamping for most of the periphery and said disc dished from part of said seat in minor peripheral portions of said disc, and said dished portions disposed in the extremities of one diameter of said disc, and means disposed between said dished peripheral portions and said seat to maintain said dished peripheral portions while rigidly clamped in operative position, the dished peripheral portions remaining secured against peripheral stretching, or gripping, or elongation, or relative flattening, the opposite parts of said dished peripheral portions of said diaphragm being clamped for security against rigid clamping of the major peripheral portion of said diaphragm such that said diaphragm is substantially free to move over its major peripheral portion.

16. A telephone receiver as set forth in claim 5 comprising a pair of strips, a magnetic plate disc and a seat thereof, and said seat and said disc clamped together intermediarily by disposing said strips between peripheral portions of said dise and said seat, and arranging said strips on said seat at the extremities of one diameter thereof,

and said disc and said seat clamped together interspacially over the major part oi said peripheral portions thereof, the dished peripheral portions remaining secured against peripheral stretching, or gripping, or elongation, or relative flattening, the opposite parts of said dished peripheral portions of said diaphragm being clamped for security against rigid clamping of the major peripheral portion of said diaphragm such that said diaphragm is substantially free to move over its major peripheral portion.

i7. A telephone receiver embracing a casing supplied with a seat, a pair of recesses arranged in the boundary line of minor peripheral portions thereof, and along one diameter oi said seat, a pair of metallic strips supported on said seat, and one leg of each strip disposed in each of said recesses, a magnetic diaphragm iinpulsing combination within said casing a magnetic diaphragm placed over said diaphragm impulsing Combination, and along one diameter of said diaphragm a pair of dishings outward from the plane of said seat and said diaphragm impulsing combination, and said dishings arranged oppositely and disposed between the center portion and said peripheral portions thereof, and along the same diameter a pair of dishings inward from the plane of said seat and arranged oppositeiy between the center portion and said peripheral portions, and one leg of each strip arranged between the dished peripheral portions of said diaphragm and said seat, and said dished peripheral portions arranged to bear against one oi said legs of each of said strips, and an outer abutment and rigid means disposed between the outer side of the marginal portions of said diaphragm and said outer abutment and adapted to apply a resisting pressure against said dished peripheral portions thereof, the dished periphn eral portions remaining secured against peripheral stretching, or gripping, or elongation, or relative flattening, the opposite parts of said dished peripheral portions of said diaphragm being clamped for security against rigid clamping of the major peripheral portion of said diaphragm such that said diaphragm is substan- 

